//导入背景图片
bg-image($url)
    background-image: url($url + "@2x.png")
    @media (-webkie-min-deivce-pixel-ratio:3),(min-deivce-pixel-ratio:3)
        background: url($url + "@3x.png")
//不换行
no-wrap()
    text-overflow:hidden
    white-space:nowrap
    overflow: hidden

//点击扩展区域
extend-click()
    position: relative
    &:before
        content:''
        position: absolute
        left: -10px
        right: -10px
        bottom: -10px
        
